Neighboring Russia has tried to moderate disputes between Armenia and Azerbaijan, despite also supplying both sides with weapons. The past week has seen grenade and mortar attacks from Armenian forces, and Azerbaijan says it's shot down an Armenian drone. (Video via Davit Sofiyan)

The two nations have an unmistakable rivalry that starts at the top of government. Azerbaijan's president, Ilham Aliyev, doesn't just boast about his country's oil riches.

On Twitter, he actively disparages Armenia, calling it powerless and poor and even writing, "It is not worthy of being a servant."

Last November, Azerbaijan shot down an army helicopter, killing three Armenian soldiers. This video, viewed hundreds of thousands of times on YouTube, claims to show that attack. (Video via Hebib Muntezir)

Last week, international mediators from France, Russia and the U.S. demanded an end to the violence. Regional experts say the fighting is as bad now as it's been since a 1994 truce divided up this territory.